Ultrasound catheter apparatus

ABSTRACT

Ultrasound catheter devices and methods of the present invention generally provide for ablation and/or disruption of vascular occlusions. An ultrasound transmission member, such as a wire, transmits vibrational energy from an ultrasound transducer to a distal head of the catheter to disrupt vascular occlusions. At least one absorber member is disposed on or around the ultrasound transmission wire at a location adjacent the sonic connector of the catheter. The absorber member absorbs heat, vibrations, and/or the like from the ultrasound transmission wire at or near the area where the transmission wire is coupled with the sonic connector. The absorptive function typically slows the process of wear and tear on the transmission wire, thus extending the useful life of the ultrasound catheter.

[0001] This application is related to pending U.S. patent applicationSer. No. 10/229,371, filed Aug. 26, 2002, entitled “Ultrasound Catheterfor Disrupting Blood Vessel Obstructions,” (Attorney Docket No.21577-000400US) the full disclosure of which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to medical devices andmethods. More specifically, the present invention relates to ultrasoundcatheter devices and methods for treating occlusive intravascularlesions.

[0003] Catheters employing various types of ultrasound transmittingmembers have been successfully used to ablate or otherwise disruptobstructions in blood vessels. Specifically, ablation of atheroscleroticplaque or thromboembolic obstructions from peripheral blood vessels suchas the femoral arteries has been particularly successful. Variousultrasonic catheter devices have been developed for use in ablating orotherwise removing obstructive material from blood vessels. For example,U.S. Pat. Nos. 5,267,954 and 5,380,274, issued to an inventor of thepresent invention and hereby incorporated by reference, describeultrasound catheter devices for removing occlusions. Other examples ofultrasonic ablation devices for removing obstructions from blood vesselsinclude those described in U.S. Pat. Nos. 3,433,226 (Boyd), U.S. Pat.No. 3,823,717 (Pohlman, et al.), U.S. Pat. No. 4,808,153 (Parisi), U.S.Pat. No. 4,936,281 (Stasz), U.S. Pat. No. 3,565,062 (Kuris), U.S. Pat.No. 4,924,863 (Sterzer), U.S. Pat. No. 4,870,953 (Don Michael, et al),and U.S. Pat. No. 4,920,954 (Alliger, et al.), as well as other patentpublications W087-05739 (Cooper), W089-06515 (Bernstein, et al.),W090-0130 (Sonic Needle Corp.), EP, EP316789 (Don Michael, et al.),DE3,821,836 (Schubert) and DE2438648 (Pohlman). While many ultrasoundcatheters have been developed, however, improvements are still beingpursued.

[0004] Typically, an ultrasonic catheter system for ablating occlusivematerial includes three basic components: an ultrasound generator, anultrasound transducer, and an ultrasound catheter. The generatorconverts line power into a high frequency current that is delivered tothe transducer. The transducer contains piezoelectric crystals which,when excited by the high frequency current, expand and contract at highfrequency. These small, high-frequency expansions and contractions haveboth longitudinal and transverse components (relative to an axis of thetransducer and the catheter), which are amplified by the transducer horninto vibrational energy. The vibrations are then transmitted from thetransducer through the ultrasound catheter via an ultrasoundtransmission member (or wire) running longitudinally through thecatheter. The transmission member transmits the vibrational energy tothe distal end of the catheter where the energy is used to ablate orotherwise disrupt a vascular obstruction.

[0005] To effectively reach various sites for treatment of intravascularocclusions, ultrasound catheters of the type described above typicallyhave lengths of about 150 cm or longer. To permit the advancement ofsuch ultrasound catheters through small and/or tortuous blood vesselssuch as the aortic arch, coronary vessels, and peripheral vasculature ofthe lower extremities, the catheters (and their respective ultrasoundtransmission wires) must typically be sufficiently small and flexible.Due to attenuation of ultrasound energy along the long, thin, ultrasoundtransmission wire, a sufficient amount of vibrational energy must beapplied at the proximal end of the wire to provide a desired amount ofenergy at the distal end.

[0006] An ultrasound transmission wire is usually coupled at itsproximal end with the transducer by means of a sonic connector. Thesonic connector typically has a significantly larger diameter than thatof the ultrasound transmission member, the difference in diametershelping to amplify the vibrational energy being transmitted from thetransducer to the transmission wire. This amplification of vibrations,however, creates stress and heat in the transmission wire in an areaadjacent its connection with the sonic connector. Stress and heatgenerated by these amplified vibrations (especially transversevibrations) significantly reduce the usable life of the ultrasoundtransmission wire and may cause its premature breakage at or near thepoint of contact with the sonic connector.

[0007] Efforts have been made to reduce transverse vibrations somewherealong the length of an ultrasound transmission member. For example, U.S.Pat. Nos. 5,382,228 and 6,494,891, both of which issued to an inventorof the present invention and are hereby incorporated by reference,describe mechanisms for absorbing transverse motion of an ultrasoundtransmission wire. Currently available devices and devices described inthe above patents, however, to not reduce stress and/or heat in anultrasound transmission wire at or near its point of contact with asonic connector as much as may be desired. As just discussed, thisproximal area of the transmission wire may be one of the most vulnerableareas due to its exposure to amplified vibrational energy from the sonicconnector.

[0008] Therefore, a need exists for an improved ultrasound catheterdevice and method that provides ablation or disruption of vascularocclusions. Ideally, the ultrasound catheter would include means forreducing heat in the ultrasound transmission wire component of thecatheter at or near its coupling with the sonic connector component.Alternatively or additionally, it would also be ideal if transversevibrations and stress were reduced in a proximal portion of thetransmission wire. Such catheter devices would ideally be sufficientlythin and flexible to be advanced through narrow, tortuous vasculature,such as the coronary vasculature, while also being configured to enhancethe usable life of the ultrasound transmission wire. At least some ofthese objectives will be met by the present invention.

BRIEF SUMMARY OF THE INVENTION

[0009] Ultrasound catheter devices and methods of the present inventiongenerally provide for ablation and/or disruption of vascular occlusions.An ultrasound transmission member, such as a wire, transmits vibrationalenergy from an ultrasound transducer to a distal head of the catheter todisrupt vascular occlusions. At least one absorber member is disposed onor around the ultrasound transmission wire at a location adjacent thesonic connector of the catheter. The absorber member absorbs heat,vibrations, and/or the like from the ultrasound transmission wire at ornear the area where the transmission wire is coupled with the sonicconnector. The absorptive function typically slows the process of wearand tear on the transmission wire, thus extending the useful life of theultrasound catheter.

[0010] In one aspect of the invention, an ultrasound catheter fordisrupting occlusions in blood vessels comprises: an elongate flexiblecatheter body having a proximal end, a distal end and at least onelumen; an ultrasound transmission member extending longitudinallythrough the lumen of the catheter body; a sonic connector coupled with aproximal end of the ultrasound transmission member for coupling theultrasound transmission member with a separate ultrasound generatingdevice; and at least one heat absorbing member coupled with theultrasound transmission member adjacent the sonic connector. In someembodiments, the heat absorbing member surrounds a portion of theultrasound transmission member adjacent a distal end of the sonicconnector. Optionally, the heat absorbing member includes a bore forreceiving the ultrasound transmission member. In some embodiments, sucha heat absorbing member is tubular.

[0011] In some embodiments, the heat absorbing member contacts a distalend of the sonic connector, while in other embodiments the heatabsorbing member may be separated from a distal end of the sonicconnector by a distance of a few millimeters. The heat absorbing membermay comprise one piece or, in other embodiments, the heat absorbingmember may comprise at least two component parts such as at least oneabsorptive part in contact with the transmission member for absorbingheat and at least one constraining part coupled with the absorptive partfor holding the absorptive part in place on the transmission member. Insome such embodiments, the constraining part contacts the transmissionmember and comprises at least one absorptive material for absorbingheat. In various embodiments, the constraining part may either contact aportion of the sonic connector or overlap a portion of the sonicconnector. Optionally, at least one of the absorptive part and theconstraining part may be capable of absorbing vibrations. In someembodiments, the constraining part comprises a bore for receiving theultrasound transmission wire, wherein the bore includes a widenedportion for receiving the absorptive part. In some embodiments, theconstraining part is tubular. Also in some embodiments, the constrainingpart is coupled with at least one of the absorptive part and theultrasound transmission wire by at least one of crimping, bonding,fusing or welding.

[0012] In other embodiments, the heat absorbing member comprises atleast two component parts comprising at least one vibration absorptivepart in contact with the transmission member for absorbing vibrationsand at least one constraining part coupled with the absorptive part forholding the absorptive part in place on the transmission member and forabsorbing heat. In some embodiments, the constraining part contacts aportion of the sonic connector, while in other embodiments it overlaps aportion of the sonic connector. In some embodiments, the constrainingpart comprises a bore for receiving the ultrasound transmission wire,wherein the bore includes a widened portion for receiving the absorptivepart. In such embodiments, the constraining part may sometimes betubular.

[0013] In some embodiments, the heat absorbing member is capable ofabsorbing vibrations. In other embodiments, the ultrasound catheterfurther includes a vibrational absorbing member coupled with theultrasound transmission member for absorbing vibrations. In either case,the heat absorbing member may comprise at least one metal having heatconductivity properties. The metal(s) may include, but are not limitedto, aluminum and its alloys, titanium and its alloys, and/or magnesiumand its alloys. Finally, in some embodiments the heat absorbing memberis coupled with the ultrasound transmission wire by at least one ofcrimping, bonding, fusing or welding.

[0014] In another aspect, an ultrasound catheter for disruptingocclusions in blood vessels includes: an elongate flexible catheter bodyhaving a proximal end, a distal end and at least one lumen; anultrasound transmission member extending longitudinally through thelumen of the catheter body; a sonic connector coupled with a proximalend of the ultrasound transmission member for coupling the ultrasoundtransmission member with a separate ultrasound generating device; and atleast one vibration absorbing member coupled with the ultrasoundtransmission member adjacent the sonic connector. Any of the featuresand combinations described for the embodiments above may be equallyapplied to this aspect of the invention.

[0015] In some embodiments, the vibration absorbing member surrounds aportion of the ultrasound transmission member adjacent a distal end ofthe sonic connector. For example, the vibration absorbing member mayinclude a bore for receiving the ultrasound transmission member. In someembodiments, the vibration absorbing member is tubular. In someembodiments, the vibration absorbing member contacts a distal end of thesonic connector, while in others it is separated from a distal end ofthe sonic connector by a distance of a few millimeters. For example, insome embodiments, the absorbing member may be separated from the sonicconnector by approximately ¼ of a wavelength produced by the ultrasounddevice.

[0016] In some embodiments, the vibration absorbing member comprises atleast two component parts, the component parts comprising: at least oneabsorptive part in contact with the transmission member for absorbingvibrations; and at least one constraining part coupled with theabsorptive part for holding the absorptive part in place on thetransmission member. In some embodiments, the at least one constrainingpart contacts the transmission member and comprises at least oneabsorptive material for absorbing heat. Also in some embodiments, the atleast one constraining part contacts or overlaps a portion of the sonicconnector. In some embodiments, at least one of the absorptive part andthe constraining part is capable of absorbing heat. In some embodiments,the at least one constraining part comprises a bore for receiving theultrasound transmission wire, wherein the bore includes a widenedportion for receiving the absorptive part. In such embodiments, theconstraining part may be tubular. The constraining part may be coupledwith at least one of the absorptive part and the ultrasound transmissionwire by at least one of crimping, bonding, fusing or welding.

[0017] In other embodiments, the vibration absorbing member comprises atleast two component parts, the component parts comprising: at least onevibration absorptive part in contact with the transmission member forabsorbing vibrations; and at least one constraining part coupled withthe absorptive part for holding the absorptive part in place on thetransmission member and for absorbing heat. The at least oneconstraining part may contact or overlap a portion of the sonicconnector in various embodiments. Optionally, the constraining part mayinclude a bore for receiving the ultrasound transmission wire, whereinthe bore includes a widened portion for receiving the absorptive part.In such embodiments, the constraining part may be tubular, for example.

[0018] In some embodiments, the vibration absorbing member is capable ofabsorbing heat. In other embodiments, the ultrasound catheter furtherincludes a heat absorbing member coupled with the ultrasoundtransmission member for absorbing heat. In some embodiments thevibration absorbing member comprises at least one vibration absorbingmaterial selected from the group consisting of rubbers and polymers. Insome embodiments, the vibration absorbing member further comprises atleast one metal having heat conductivity properties. For example, such ametal may be selected from the group consisting of aluminum, titanium,and magnesium. In some embodiments, the vibration absorbing member iscoupled with the ultrasound transmission wire by at least one ofcrimping, bonding, fusing or welding.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view of an ultrasound catheter systemconstructed according to the principles of the present invention.

[0020]FIG. 2 is a cross-sectional view of an ultrasound catheter havingan absorber member according to an embodiment of the present invention.

[0021]FIG. 3A is a magnified view of a proximal end of an ultrasoundcatheter as shown in FIG. 2.

[0022]FIG. 3B is a further magnified view of a proximal end of anultrasound catheter as shown in FIGS. 2 and 3A.

[0023] FIGS. 4A-4C are cross-sectional views of proximal ends ofultrasound catheters having absorber members according to variousembodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] Ultrasound catheter devices and methods of the present inventiongenerally provide for ablation and/or disruption of vascular occlusions.An ultrasound transmission member, such as a wire, transmits vibrationalenergy from an ultrasound transducer to a distal head of the catheter todisrupt vascular occlusions. At least one absorber member is disposed onor around the ultrasound transmission wire at a location adjacent thesonic connector of the catheter. The absorber member absorbs heat,vibrations, and/or the like from the ultrasound transmission wire at ornear the area where the transmission wire is coupled with the sonicconnector. The absorptive function typically slows the process of wearand tear on the transmission wire, thus extending the useful life of theultrasound catheter. Although catheters of the invention are describedin detail below, for further details reference may be made to U.S.patent application Ser. No. 10/229,371, filed Aug. 26, 2002, which waspreviously incorporated by reference.

[0025] Referring now to FIG. 1, one embodiment of an over-the-wireultrasound catheter system 20 suitably includes an ultrasound catheter10, a proximal end connector assembly 12 coupled with catheter 10, anultrasound transducer 14 coupled with the proximal end of proximalconnector assembly 12, and an ultrasound generator 16 with afoot-actuated on/off switch 18, which is operatively coupled withultrasound transducer 14 to provide ultrasonic energy to transducer 14and, thus, to ultrasound catheter 10. Generally, catheter 10 willinclude an ultrasound transmission member, or wire (not shown), fortransmitting energy from the transducer 14 to a distal head 26 of thecatheter. Proximal connector assembly 12, described more fully below,may have a Y-connector 15 with one or more side-arms 13, for example forproviding irrigation fluid via an irrigation tube 11. The catheter 10may be passed along a guide wire 17 which accesses catheter 10 via aside aperture. The side aperture may be located close to the distal endof catheter 10 or in another embodiment (not shown) close to theproximal end of catheter 10.

[0026] Ultrasound catheters 10 of the present invention may be used withany suitable combination of devices, such as any suitable ultrasoundtransducer 14, ultrasound generator 16, and/or the like. Therefore,exemplary FIG. 1 and any following descriptions of ultrasound catheterapparatus or systems should in no way be interpreted to limit the scopeof the present invention as defined in the appended claims. Again,exemplary ultrasound catheters which may incorporate one or moreimprovements of the present invention are described in previouslyincorporated U.S. patent application Ser. No. 10/229,371. Otherexemplary catheters are described in U.S. patent application Ser. No.10/345,078, filed on Jan. 14, 2003, entitled “Ultrasound Catheter andMethods for Making and Using Same,” by an inventor of the presentinvention, the full disclosure of which is hereby incorporated byreference. On the other hand, any suitable ultrasound catheter now knownor hereafter discovered may be configured to include one or moreimprovements of the present invention and, thereby, fall within thescope of the invention.

[0027] Referring now to FIGS. 2 and 3, cross-sectional side views ofultrasound catheter 10 and a proximal portion of ultrasound catheter 10are shown, respectively. Generally, ultrasound catheter 10 suitablyincludes an elongate catheter body 22 with an ultrasound transmissionmember 24 disposed longitudinally through its lumen and ending in distalhead 26. Catheter body 22 is generally a flexible, tubular, elongatemember, having any suitable diameter and length for reaching a vascularocclusion for treatment. In one embodiment, for example, catheter body22 preferably has an outer diameter of between about 0.5 mm and about5.0 mm. In other embodiments, as in catheters intended for use inrelatively small vessels, catheter body 22 may have an outer diameter ofbetween about 0.25 mm and about 2.5 mm. Catheter body 22 may also haveany suitable length. As discussed briefly above, for example, someultrasound catheters have a length in the range of about 150 cm.However, any other suitable length may be used without departing fromthe scope of the present invention. Examples of catheter bodies similarto those which may be used in the present invention are described inU.S. Pat. Nos. 5,267,954 and 5,989,208, which were previouslyincorporated herein by reference.

[0028] In most embodiments, ultrasound transmission member 24, wire, orwave guide extends longitudinally through catheter body lumen 21 totransmit ultrasonic energy from ultrasound transducer 14, connected tothe proximal end of catheter 10, to the distal end of catheter 10.Ultrasound transmission member 24 may be formed of any material capableof effectively transmitting ultrasonic energy from ultrasound transducer14 to the distal end of catheter body 22, including but not limited tometals such as pure titanium or aluminum, or titanium or aluminumalloys.

[0029] In accordance with one aspect of the invention, all or a portionof ultrasound transmission member 24 may be formed of one or morematerials which exhibit superelastic properties. Such material(s) shouldpreferably exhibit superelasticity consistently within the range oftemperatures normally encountered by ultrasound transmission member 24during operation of ultrasound catheter apparatus 10. Specifically, allor part of the ultrasound transmission member 24 may be formed of one ormore metal alloys known as “shape memory alloys.”

[0030] Use of supereleastic metal alloys in ultrasound transmissionmembers is described in U.S. Pat. No. 5,267,954, previously incorporatedby reference. Examples of superelastic metal alloys which may be usedare described in detail in U.S. Pat. Nos. 4,665,906 (Jervis); U.S. Pat.No. 4,565,589 (Harrison); U.S. Pat. No. 4,505,767 (Quin); and U.S. Pat.No. 4,337,090 (Harrison). The disclosures of U.S. Pat. Nos. 4,665,906;4,565,589; 4,505,767; and 4,337,090 are expressly incorporated herein byreference insofar as they describe the compositions, properties,chemistries and behavior of specific metal alloys which are superelasticwithin the temperature range at which the ultrasound transmission memberof the present invention operates, any and all of which superelasticmetal alloys may be used to form ultrasound transmission member 24 ofthe present invention.

[0031] In many embodiments, ultrasound transmission member 24 includesone or more tapered regions along a portion of its length, towards itsdistal end. Such a tapered region decreases the distal rigidity ofultrasound transmission member 24, thus amplifying ultrasound energytransmitted along ultrasound transmission member 24 to distal head 26.The tapered region typically divides the transmission member 24 betweena proximal portion and a distal portion, which both typically have alarger cross-sectional diameter than the tapered region. A thickerdistal portion, for example, may enhance stability of the connectionbetween ultrasound transmission member 24 and distal head 26. Otherembodiments are contemplated, however. For example, the tapered regionmay be positioned at the extreme distal end of transmission member 24.In still other embodiments, ultrasound transmission member 24 mayinclude multiple tapered portions, widened portions and/or the like.Thus, ultrasound transmission member 24 may be configured with anysuitable length, combinations of diameters and tapers, or any othersuitable shapes, sizes or configurations to advantageously transmitultrasound energy from transducer 14 to distal tip 26.

[0032] In some embodiments ultrasound transmission member 24 may includea low-friction coating or jacket on all or a portion of its outersurface. The coating may be disposed on the outer surface of ultrasoundtransmission member 24 so as to completely cover ultrasound transmissionmember 24 along its entire length, or along a discrete region or regionsthereof. Such a coating or jacket may comprise a layer of low frictionpolymer material such as polytetrafluoroethylene (PTFE), TEFLON™(available from DUPONT, INC., Wilmington, Del.) or other plasticmaterials such as polyethylene. The coating may be applied as a liquidand subsequently allowed to cure or harden on the surface of ultrasoundtransmission member 24. Alternatively, the coating may be in the form ofan elongate tube, disposable over the outer surface of ultrasoundtransmission member 24. Generally, the coating serves to prevent ordiminish friction between the outer surface of ultrasound transmissionmember 24 and the adjacent structures of catheter 10 or proximal endconnector assembly 12 through which ultrasound transmission member 24extends.

[0033] With continued reference to FIGS. 2 and 3A, one embodiment ofproximal end connector assembly 12 suitably includes a housing 42 with ahollow inner bore 44. Bore 44 may have a uniform inner diameter alongits length or, alternatively, may have multiple segments, such as aproximal segment 47, a middle segment 45 and a distal segment 49, eachof which may surround one or more various components of proximal endconnector apparatus 12. Generally, proximal segment 47 of bore 44 isconfigured to allow coupling with ultrasound transducer 14 (not shown)via any suitable coupling means, such as a pressure fit, complementarythreads or the like. Proximal segment 47 includes a sonic connector 52for transmitting vibrational energy from transducer 14 to ultrasoundtransmission member 24. In some embodiments, sonic connector 52 may beheld within housing 42, by means of dowel pin 53. In other embodiments,dowel pin 53 may not be included and sonic connector 52 may bepositioned within housing 42 by other means.

[0034] Middle segment 45 of bore 44, in some embodiments, may surround aportion of sonic connector 52, while in other embodiments, sonicconnector 52 may be housed only within proximal segment 47. Sonicconnector 48 is coupled with the distal end of ultrasound transmissionmember 24 by any suitable means for transmitting ultrasound energy totransmission member 24 from transducer 14. An absorber member 50 isdisposed around at least a portion of ultrasound transmission member 24immediately distal and immediately adjacent to sonic connector 52.Absorber member 50 is described in further detail below, but generallyis configured to abut sonic connector 52 to absorb heat and/ortransverse vibrations from, and therefore reduce wear and tear on,ultrasound transmission member 24. Optionally, some embodiments furtherinclude one or more O-rings 46 distal to absorber member 50 and disposedabout ultrasound transmission member 24 for providing further absorptionof transverse vibration. Absorber member 50 and O-rings 46 may be usedin any number or combination and have and suitable size andconfiguration, depending on the desired level of vibration absorption ordampening. Alternatively or additionally, other dampening structures maybe used. Thus, the invention is not limited to the combination shown inFIG. 2.

[0035] Distal segment 49 of bore 44 typically surrounds a portion ofultrasound transmission member 24 and may also contain one or moreadditional sets of absorber members 46. Distal segment 49 may alsocontain a portion of a Y-connector 15, which is coupled with the distalend 43 of housing 42 of proximal end connector apparatus 12. Coupling ofY-connector 15 with distal end 43 of proximal end connector assembly 12may be accomplished via complementary threads, pressure fitting, or anyother suitable means. A Y-connector lumen 48 of Y-connector 15 allowspassage of ultrasound transmission member 24 and is in communicationwith the catheter body lumen.

[0036] Generally, pressurized fluid such as a coolant liquid may beinfused through side-arm 13, through Y-connector lumen 45 and throughthe catheter body lumen so that it flows out of one or more fluidoutflow apertures in distal head. The temperature and flow rate of suchcoolant liquid may be specifically controlled to maintain thetemperature of ultrasound transmission member 24 at a desiredtemperature within its optimal working range. In particular, inembodiments of the invention wherein ultrasound transmission member 24is formed of a metal alloy which exhibits optimal physical properties(e.g. super elasticity) within a specific range of temperatures, thetemperature and flow rate of coolant liquid infused through fluidinfusion side-arm 13 may be specifically controlled to maintain thetemperature of ultrasound transmission member 24 within a range oftemperatures at which it demonstrates its most desirable physicalproperties. For example, in embodiments of the invention whereinultrasound transmission member 24 is formed of a shape memory alloywhich exhibits super elasticity when in its martensite state, but whichloses super elasticity as it transitions to an austenite state, it willbe desirable to adjust the temperature and flow rate of the coolantliquid infused through fluid infusion side-arm 13 so as to maintain theshape memory alloy of ultrasound transmission member 24 within atemperature range at which the alloy will remain in its martensite stateand will not transition to an austenite state. The temperature at whichsuch shape memory alloys transition from a martensite state to anaustenite state is known as the “martensite transition temperature” ofthe material. Thus, in these embodiments, the fluid infused throughside-arm 13 will be at such temperature, and will be infused at suchrate, as to maintain the shape memory alloy of ultrasound transmissionmember 24 below its martensite transition temperature.

[0037] Referring to FIGS. 3A and 3B, one embodiment of absorber member50 of the present invention is shown disposed about ultrasoundtransmission wire 24 and immediately adjacent the distal end of sonicconnector 52. Generally, absorber member 50 may have any suitable size,shape or configuration, may be made of any suitable material, and may becoupled with ultrasound transmission member 24 by any suitable means toprovide for absorption or dampening of heat, transverse vibrations,other unwanted stresses on ultrasound transmission member 24 and/or thelike. Typically, absorber member 50 is made from relatively light-weightmaterial(s), so that little or no additional load is placed on thetransmission wire. In some embodiments, absorber member 50 comprises oneor more materials having heat transfer properties for absorbing heatfrom ultrasound transmission member 24. Essentially, such an absorbermember 50 acts as a heat sink to help prevent ultrasound transmissionmember from increasing in temperature to a level which may increase wearand tear of transmission member 24. Materials which may be used forproviding absorber member with heat absorption properties, for example,may include but are not limited to aluminum and its alloys, magnesiumand it alloys and/or titanium and its alloys.

[0038] Absorber member 50 may be coupled with ultrasound transmissionmember 24 by any suitable means. In some embodiments, for example,absorber member 50 may be positioned at a desired location ontransmission member 24 during manufacturing and then may be crimped,using a crimping device, to adhere to transmission member 24. Othermethods for coupling absorber member 50 with transmission member 24 arealso contemplated, such as pressure fitting, use of adhesive substances,and the like.

[0039] Absorber members 50 of the present invention are generallypositioned on transmission member 24 at a location adjacent to thedistal end of sonic connector 52. As shown in FIG. 3A, in someembodiments absorber member 50 is positioned immediately adjacent andabutting the distal end of sonic connector 52. In other embodiments, asin FIG. 3B, absorber member 50 may be disposed very close to the distalend of sonic connector 52 without actually abutting or touching sonicconnector 52. In various embodiments, for example, the distance betweenthe distal end of sonic connector 52 and the proximal end of absorbermember 50 may range up to a few millimeters.

[0040] With reference now to FIGS. 4A and 4C, various embodiments ofproximal end connector apparatus 12 may include an absorber member 50having two or more component parts and/or comprising two or moredifferent materials. For example, in some embodiments absorber member 50includes a vibrational absorber 58 immediately surrounding transmissionmember 24 and a constraining member 56 immediately surroundingvibrational absorber 58. In various embodiments, vibrational absorber 58and/or constraining member 56 may be configured to absorb transversevibrations, absorb/transfer heat, or both. In some embodiments, forexample, vibrational absorber 58 is made from a polymer or plasticcapable of absorbing both vibrations and heat, while constraining member56 is configured primarily to hold vibrational absorber 58 in place ontransmission member 24.

[0041] In other embodiments, for example as in FIG. 4B, a differentlyshaped constraining member 64 may include one or more heat absorptivematerials, and part of constraining member 64 may contact transmissionmember 24 or be disposed in close proximity to transmission member 24 toabsorb heat generated in transmission member 24. Constraining member 64may also absorb vibrations in some embodiments. In various embodiments,therefore, constraining member 56, 64 may serve a constraining function,a vibrational absorption function, a heat absorption function, or anycombination thereof.

[0042] Referring now to FIG. 4C, another embodiment of absorber member50 includes a constraining member 68 that overlaps a distal portion ofsonic connector 52. Again, such a constraining member 68 may provide forvibration and/or heat absorption in addition to the constrainingfunction. In such overlapping embodiments, vibrational absorber 58 maydirectly abut the distal end of sonic connector 52 or may be spacedapart from sonic connector 52, as shown in FIG. 4C. Generally, absorbermembers 50 of the invention will include at least one part that abuts oris closely adjacent to sonic connector 52, but may include one or moreparts that are separate as well, as in FIG. 4C. As is evident from FIGS.4A-4C, absorber member 50 may include any suitable combination ofcomponent parts having any suitable configuration and comprising anysuitable combination of materials. In other embodiments, of course,absorber member 50 may comprise one, unitary piece, may comprise morethan two components parts, or the like.

[0043] Although the invention has been described above with specificreference to various embodiments and examples, it should be understoodthat various additions, modifications, deletions and alterations may bemade to such embodiments without departing from the spirit or scope ofthe invention. Accordingly, it is intended that all reasonablyforeseeable additions, deletions, alterations and modifications beincluded within the scope of the invention as defined in the followingclaims.

What is claimed is:
 1. An ultrasound catheter for disrupting occlusionsin blood vessels, the ultrasonic catheter comprising: an elongateflexible catheter body having a proximal end, a distal end and at leastone lumen; an ultrasound transmission member extending longitudinallythrough the lumen of the catheter body; a sonic connector coupled with aproximal end of the ultrasound transmission member for coupling theultrasound transmission member with a separate ultrasound generatingdevice; and at least one heat absorbing member coupled with theultrasound transmission member adjacent the sonic connector.
 2. Anultrasound catheter as in claim 1, wherein the heat absorbing membersurrounds a portion of the ultrasound transmission member adjacent adistal end of the sonic connector.
 3. An ultrasound catheter as in claim2, wherein the heat absorbing member includes a bore for receiving theultrasound transmission member.
 4. An ultrasound catheter as in claim 3,wherein the heat absorbing member is tubular.
 5. An ultrasound catheteras in claim 1, wherein the heat absorbing member contacts a distal endof the sonic connector.
 6. An ultrasound catheter as in claim 1, whereinthe heat absorbing member is separated from a distal end of the sonicconnector by a distance of approximately ¼ wavelength of an ultrasoundwave transmitted to the ultrasound catheter.
 7. An ultrasound catheteras in claim 1, wherein the heat absorbing member comprises at least twocomponent parts, the component parts comprising: at least one absorptivepart in contact with the transmission member for absorbing heat; and atleast one constraining part coupled with the absorptive part for holdingthe absorptive part in place on the transmission member.
 8. Anultrasound catheter as in claim 7, wherein the at least one constrainingpart contacts the transmission member and comprises at least oneabsorptive material for absorbing heat.
 9. An ultrasound catheter as inclaim 8, wherein the at least one constraining part contacts a portionof the sonic connector.
 10. An ultrasound catheter as in claim 8,wherein the at least one constraining part overlaps a portion of thesonic connector.
 11. An ultrasound catheter as in claim 7, wherein atleast one of the absorptive part and the constraining part is capable ofabsorbing vibrations.
 12. An ultrasound catheter as in claim 7, whereinthe at least one constraining part comprises a bore for receiving theultrasound transmission wire, wherein the bore includes a widenedportion for receiving the absorptive part.
 13. An ultrasound catheter asin claim 12, wherein the constraining part is tubular.
 14. An ultrasoundcatheter as in claim 12, wherein the constraining part is coupled withat least one of the absorptive part and the ultrasound transmission wireby at least one of crimping, bonding, fusing or welding.
 15. Anultrasound catheter as in claim 1, wherein the heat absorbing membercomprises at least two component parts, the component parts comprising:at least one vibration absorptive part in contact with the transmissionmember for absorbing vibrations; and at least one constraining partcoupled with the absorptive part for holding the absorptive part inplace on the transmission member and for absorbing heat.
 16. Anultrasound catheter as in claim 15, wherein the at least oneconstraining part contacts a portion of the sonic connector.
 17. Anultrasound catheter as in claim 16, wherein the at least oneconstraining part overlaps a portion of the sonic connector.
 18. Anultrasound catheter as in claim 15, wherein the at least oneconstraining part comprises a bore for receiving the ultrasoundtransmission wire, wherein the bore includes a widened portion forreceiving the absorptive part.
 19. An ultrasound catheter as in claim18, wherein the constraining part is tubular.
 20. An ultrasound catheteras in claim 1, wherein the heat absorbing member is capable of absorbingvibrations.
 21. An ultrasound catheter as in claim 1, further comprisinga vibrational absorbing member coupled with the ultrasound transmissionmember for absorbing vibrations.
 22. An ultrasound catheter as in claim1, wherein the heat absorbing member comprises at least one metal havingheat conductivity properties.
 23. An ultrasound catheter as in claim 22,wherein the at least one metal is selected from the group consisting ofaluminum, aluminum alloys, titanium, titanium alloys, magnesium, andmagnesium alloys.
 24. An ultrasound catheter as in claim 1, wherein theheat absorbing member is coupled with the ultrasound transmission wireby at least one of crimping, bonding, fusing or welding.
 25. Anultrasound catheter for disrupting occlusions in blood vessels, theultrasonic catheter comprising: an elongate flexible catheter bodyhaving a proximal end, a distal end and at least one lumen; anultrasound transmission member extending longitudinally through thelumen of the catheter body; a sonic connector coupled with a proximalend of the ultrasound transmission member for coupling the ultrasoundtransmission member with a separate ultrasound generating device; and atleast one vibration absorbing member coupled with the ultrasoundtransmission member adjacent the sonic connector.
 26. An ultrasoundcatheter as in claim 25, wherein the vibration absorbing membersurrounds a portion of the ultrasound transmission member adjacent adistal end of the sonic connector.
 27. An ultrasound catheter as inclaim 26, wherein the vibration absorbing member includes a bore forreceiving the ultrasound transmission member.
 28. An ultrasound catheteras in claim 27, wherein the vibration absorbing member is tubular. 29.An ultrasound catheter as in claim 25, wherein the vibration absorbingmember contacts a distal end of the sonic connector.
 30. An ultrasoundcatheter as in claim 25, wherein the vibration absorbing member isseparated from a distal end of the sonic connector by a distance ofapproximately ¼ wavelength of an ultrasound wave transmitted to theultrasound catheter.
 31. An ultrasound catheter as in claim 25, whereinthe vibration absorbing member comprises at least two component parts,the component parts comprising: at least one absorptive part in contactwith the transmission member for absorbing vibrations; and at least oneconstraining part coupled with the absorptive part for holding theabsorptive part in place on the transmission member.
 32. An ultrasoundcatheter as in claim 31, wherein the at least one constraining partcontacts the transmission member and comprises at least one absorptivematerial for absorbing heat.
 33. An ultrasound catheter as in claim 32,wherein the at least one constraining part contacts a portion of thesonic connector.
 34. An ultrasound catheter as in claim 32, wherein theat least one constraining part overlaps a portion of the sonicconnector.
 35. An ultrasound catheter as in claim 31, wherein at leastone of the absorptive part and the constraining part is capable ofabsorbing heat.
 36. An ultrasound catheter as in claim 31, wherein theat least one constraining part comprises a bore for receiving theultrasound transmission wire, wherein the bore includes a widenedportion for receiving the absorptive part.
 37. An ultrasound catheter asin claim 36, wherein the constraining part is tubular.
 38. An ultrasoundcatheter as in claim 36, wherein the constraining part is coupled withat least one of the absorptive part and the ultrasound transmission wireby at least one of crimping, bonding, fusing or welding.
 39. Anultrasound catheter as in claim 25, wherein the vibration absorbingmember comprises at least two component parts, the component partscomprising: at least one vibration absorptive part in contact with thetransmission member for absorbing vibrations; and at least oneconstraining part coupled with the absorptive part for holding theabsorptive part in place on the transmission member and for absorbingheat.
 40. An ultrasound catheter as in claim 39, wherein the at leastone constraining part contacts a portion of the sonic connector.
 41. Anultrasound catheter as in claim 39, wherein the at least oneconstraining part overlaps a portion of the sonic connector.
 42. Anultrasound catheter as in claim 39, wherein the at least oneconstraining part comprises a bore for receiving the ultrasoundtransmission wire, wherein the bore includes a widened portion forreceiving the absorptive part.
 43. An ultrasound catheter as in claim42, wherein the constraining part is tubular.
 44. An ultrasound catheteras in claim 25, wherein the vibration absorbing member is capable ofabsorbing heat.
 45. An ultrasound catheter as in claim 25, furthercomprising a heat absorbing member coupled with the ultrasoundtransmission member for absorbing heat.
 46. An ultrasound catheter as inclaim 25, wherein the vibration absorbing member comprises at least onevibration absorbing material selected from the group consisting of arubber, a polymer, and a rubber/polymer combination.
 47. An ultrasoundcatheter as in claim 46, wherein the vibration absorbing member furthercomprises at least one metal having heat conductivity properties.
 48. Anultrasound catheter as in claim 47, wherein the at least one metal isselected from the group consisting of aluminum, aluminum alloys,titanium, titanium alloys, magnesium, and magnesium alloys.
 49. Anultrasound catheter as in claim 25, wherein the vibration absorbingmember is coupled with the ultrasound transmission wire by at least oneof crimping, bonding, fusing or welding.